Al-Kāfi
Hadith 173710ـ وَبِإِسْنَادِهِ عَنْ أَبِي عَبْدِ الله (عَلَيهِ السَّلام) قَالَ قَالَ الله عَزَّ وَجَلَّ لِمُوسَى اجْعَلْ لِسَانَكَ مِنْ وَرَاءِ قَلْبِكَ تَسْلَمْ وَأَكْثِرْ ذِكْرِي بِاللَّيْلِ وَالنَّهَارِ وَلا تَتَّبِعِ الْخَطِيئَةَ فِي مَعْدِنِهَا فَتَنْدَمَ فَإِنَّ الْخَطِيئَةَ مَوْعِدُ أَهْلِ النَّارِ.
10. Through the same chain of narrators it is narrated from Abu ‘Abdillah (a.s.) who has said the following: “Allah, the Most Majestic, the Most Holy, has said to Moses, ‘Keep your tongue behind your heart and you will remain safe. Speak of Me very often during the day and night. Do not follow a sin in its pit (sinful people) or you will regret. Sin is the promised place of the people of fire.’”